Christmas bonus calculation

[mrcactus]

Hi all.
I had a reply back from my IP with regards to the extra payment I have to make from my Christmas bonus I received from work.

The breakdown of my monthly wages are as follows:
Before tax: £1413.36 + £250(bonus) = £1663.36
After tax, NI and pension (£298.42) = £1364.94

My IP says an additional payment based on that payslip is £105.57.
No matter which way I work it out, I can not come to the same figure myself. The terms in my IVA are the standard 10% additional income plus 50% of extra (or what ever it's worded as)

Unless my maths is that bad, I just can't get to the same figure. Could someone clear this up for me please?
Many thanks

[Foggy]

What is your usual (already agreed) monthly take home ?

[mrcactus]

What is your usual (already agreed) monthly take home ?

It's around the £1200 mark after tax. I've never had to pay extra anyway apart from now because of this bonus.

[Foggy]

OK -- I would calculate as follows:

Basic agreed pay £1200 Therefore 10% disregard is £120

Pay above the normal amount is £1365 (rounded up) so excess is 1365 - 1200 = £165
Take off the disregard of £120 -- this leaves £45

Split 50 / 50 gives £22.50 payable to the IVA
Even without the 10% disregard you would be splitting £165, so paying £82.50.

You need to go back to them and ask for a detailed, written, calculation --- something is amiss somewhere !